In the late 19th century, German psychologist Hermann Ebbinghaus conducted a series of grueling experiments on himself. He memorized thousands of nonsense syllables and meticulously tracked how long it took him to forget them.
The result was the famous Forgetting Curve.
Ebbinghaus discovered that memory decay is exponential. Within 24 hours of learning something new, you forget nearly 70% of it. Within a week, that number drops to 10%. This is why cramming for a Spanish test works on Friday but leaves you completely incapable of speaking Spanish on Monday.
However, Ebbinghaus discovered a hack in the human source code. If you review the information just as you are about to forget it, the memory is pushed back up to 100%.
More importantly, the rate of decay slows down.
Eventually, the curve flatlines. The memory becomes permanent. This phenomenon is known as the Spacing Effect.
Spaced Repetition Software (SRS) like Anki automates this process by using algorithms to predict exactly when you are about to forget a word, and scheduling your review for that exact day.
Recall Runner takes this a step further. We embedded a world-class Spaced Repetition Algorithm into the core loop of a 3D arcade game. The game tracks your speed, accuracy, and physical hesitation during runs to mathematically calculate your mastery.
You don't need to manually click "Hard" or "Easy" like you do in Anki. The game automatically adapts the obstacle courses, bringing back the words you are struggling with and spacing out the ones you've mastered.
The result is absolute language retention, fully automated.